Code Definition

P1860 — TCC PWM Solenoid Circuit Failure

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: Isuzu

About P1860

P1860 is a manufacturer-specific powertrain diagnostic trouble code recorded for Isuzu vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1860 is stored, the module has detected an electrical-circuit fault in the wiring, connector, or driver associated with the named component.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P1860 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

This Isuzu DTC is set when the Transmission Control Module (TCM) detects a fault in the torque converter clutch (TCC) pulse width modulated (PWM) solenoid circuit. The TCC PWM solenoid regulates engagement of the torque converter clutch in a controlled, gradual manner to improve driveability and reduce harshness. The code is triggered when the TCM senses an open, a short to ground, a short to voltage, or incorrect current draw in the solenoid control circuit during operation. The driver may notice converter shudder, no lockup, a stall when coming to a stop, slipping, or reduced fuel economy.

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